SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '91467c22642bccbe3fdfa188b2f5fd934bed633fa21ae5d46d1411c58b09f6f0' 
  AND token = 'j0wdhxXQlwnbRCj+VDe3jVh7VJkhZAgZWD5TLn+trl0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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