SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'f5072517b666e47d76b4de046d598b7539846c331575299d2ff4364a015c13f8' 
  AND token = 'uSfAaup3hVV4F51dyHMY3kfMjTVAhWcQvpKaw5SZuhg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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