SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '86574ceae488b6a030e99675745a80216c549aca80fe26c23a0d7c7f0fa2a1a7' 
  AND token = '8KMOinFnPc+YMV3vz/f9K49ZC019wUiQqPZEgUPbje4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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