SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'a3dd7480b57fb26cee11d1870e62944f58945e42b06dc60202de1c9bf4f7b491' 
  AND token = 'TjIxb5YLHOtywg5l+j9v3zRaDlwHHm5GY5p8RzlGrRQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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