SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a9f1e40a001c549efcf8f5846d006f19bf244f605b698cc2cee382a4865918e7' 
  AND token = 'zoFZFnq4TmMh1ZrDjpkiYVEFjnMPmlcLgtIaM5SsQdw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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