SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '28fb2652e42f4bbd21bc425fcbe9fae2ba16fb0819846fe57fbaa3ff3c5a70c2' 
  AND token = '3OY60j0K7GF5d7qz9ANiJPSgaL/jubGb9Wf/+ShvzzA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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