SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '75f837b8d81b82773c9111231ff7874c97e2c9d5fc1985233d4ecff21dace72c' 
  AND token = 'BlK6pJEvvFyiAN41Otgs1UhMOaqR/JrLBmItwKsOIfo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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