SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3649252f38ff8a273a11288eda2947cbd69059c61b319790ef8b2d9e2cecce36' 
  AND token = 'P68H8niZ3jQ+tVXnDJo51Z14Gc/sswwfBqcYM+xG/Xw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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