SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fb4d52ceb346c92b4745868180794ccc998b55d36676c8fa83e65d8b395bcadf' 
  AND token = '/e2DqbOhqF7dFLybp/8PtW6vYSrc1fJWHAD3BuzJwXw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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