SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fed62afdf5b517b0d4c5c80988fe23913b07aa7b254b281d4000205c114e84a7' 
  AND token = 'pKFQ4ZTm9BoMbgzrz4TUX4oanwMlip3CSwMuw+1a3VY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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