SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '95275302dda6398d62ce3868075c51aea95a87f3856bb258c03c89325996a4ee' 
  AND token = 'ufmOu9ij+XydZNIcnxwFCwOa13JD2TZT2QfziH1zZxw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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