SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '7c2a1421a1f1043b88685922531c67594faaabc25afb6ded2bc566b4a09a46a8' 
  AND token = 'mrTkKJPYXK7uHjCBKw7jYDFxtfimokRXIni40O8d8VU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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