SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '785155ae2b03e4a963c7dfdbe3a4c0a69f07da3e3f80b4cd7c33be438cbf2b21' 
  AND token = 'gkwAL8M2m735kuGYgGH5sAPuTtc/ZlQKUhzIy2CidCQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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