SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3f9dbfda70aea0991afdc33b0f5e007c3ecec1f26b5b0d7131ac2d5201a5a64f' 
  AND token = 'X2vCHC5WHnflynZ1G5ESBZadKTHm4uztuQ67JP6dYLw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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