SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a95259ca16886a322dbfdadf261d2b1f5d9f170bd77987d192a3026c63a868d8' 
  AND token = 'i+lX3hcagzxWL15fKZxj+0xbFPg6/HSTm0mJwpoKYb8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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