SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cff663c78a8c8c77331f3c94f932c0ff1c0339d82242c4267084e78c63a6f841' 
  AND token = 'B0MmWL/FSOVGkyU8kUCaVjLLgYYAae/jqhpKgCt9JB8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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