SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b6e6864b903c952eda710130f219733cd52aa2268c94bbcd0b7c5a756538585b' 
  AND token = 'InsBHBzV0IMXqB1RDvjpin4YQiyQQ4e9zw7Oh/24dEo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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