SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3ce066230d03bb09b1eb799a806f4c29638b02964d44731e67c3a71dbefdc8f8' 
  AND token = 'KKIp4w0CAcJB6tzN0d4wMZQPxoAZ11kTzFw85nLkzlw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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