SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7b03b7af6d457cfd42b1f1d7c97efd4d64cbb96d7b834c87ce2a243416dd0f8a' 
  AND token = 'HFllBHV9K+oEPWiJf2GPkDVwyKC8tJS7RVbTQvDZTgY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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