SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '588a915a39f03f6784f521c880c6a8b9406ee0585ac314171b2837fb0bf513f4' 
  AND token = 'o/kdzzlCWTxjZEGh85qjQ3SBTRk9w0xY4yJS1LEHDPs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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