SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'a6eb5d85f6494bfa65380fe451db07ba38e9da09fd1730d26034441c64ab4346' 
  AND token = '/TeKrr6KBlozByowIFfypCuMeVXM+2t5ZVd9VP0lJZ8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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