SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '084f10c1fb2f7b8f0584824e2391be1016d5506e60d056fa40c1204b4376f1f2' 
  AND token = 'uM0achhAYptCvvhjRFOznhzwuB4fujjSiJmqpAoaGeE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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