SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cf3ec4d22954fdfd618ead8a72b531cac1f4b52ad8a44695c9f1944290c40979' 
  AND token = 'haB/pOX3kr0oY0w5aBegBejh+hXzW4LLvGb/yElwU5I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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