SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4eb592edf9405d77681abebd810abc40b914f5c95608a2f6346f3b28d9c05320' 
  AND token = 'ydpQqcFAdWmzAX2es+GFI6x308sCeghkvltr6EegqcM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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