SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cf42ca81de6874d05949165077346a3b00eb0193db30ea8dcf304ad8639bb672' 
  AND token = 'lKdcGudzMUk6P34dY4K4/pYBU6T4bEgkeuP8ZtpWhWk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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