SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9bcb3c412d063f1a8fa2ab0a94f9d2cab043d1e1bf2890dbc56c1f18442e5190' 
  AND token = '7MuWy4Qq1nEezmtsL7wrm7ZLZ5M2+WaCJVOj9re2L8g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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