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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b475d3ffaf60af9d89208f8d66e351b4f0d3e4365d93bc14a2175f90c4d34ff9' 
  AND token = 'HyqjMazgN73Dua+HsvqGNZMmqGfiPdT+AGMfq7Ygt7k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}