SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c1f08cc6d5a36e1d128f8e2f0953b64042cc6a4bb016132bba8be216d5200975' 
  AND token = 'xxMALRUgXMHvovWuKLtvQy15Dm9tepn1JwnIXc05pxE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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