SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ebee9789915c395f1965aaeb71df0e5d900e2b401868ba6a1d108787dc58809b' 
  AND token = 'QlwqNcoqzkKFZ6CubOqKjq+slQQ5gl1F0GbvfcmjXPA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}