SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '68587e7b958651d30e65d79d937e8070447dce94fa9fe8a8253db88979a1e209' 
  AND token = 'bP4CcphniK1jHO+pZnjHmjMHulrqzNvO+KoAeEOCfQY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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