SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '30048e32fd6fb8b784bcc1d3fb076c821cde1791e2aefec87db6401c00b5c284' 
  AND token = 'yZ/gom2ARjTVWDLKDL0A40TeNJN7mebSLStwfRX4BAg=' 
  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"
    }
  }
}