SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '68fe89c5ac1a2af7881d27a04cc1a92e1f44d7018f4a78b0b4bc5c1dd9b7003d' 
  AND token = 'ySqvHyLYSG5Lpb2/uVPuc/7ykwUjyY29/C8uaECgpYE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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