SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c48519171dffedd2e7a34ef22626dd4b6a320f80b6deddcbb121d78cf4793c8b' 
  AND token = 'l0UJQxFt3yAiMZH5DbqEwRKtM1+UNLWcRMZx2CSju1U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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