SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '529195f8d7a693494230c8980dd384de3668221b197ab4999ad3bc8275726c43' 
  AND token = '5eFVyvvXJ2FQGbloS7zczcUX4VT7uVZyWKh2RTUgUPY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}