SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'a2e7e2ff5c12b24c75c5cb42342160fe4bfbcb2d0996ad7b060b87371d61c1f5' 
  AND token = 'z7oX+84Ev4wQWYlssuvzfgJ+OAlvhRJpkHQyU/if7qY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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