SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e0109e23ed495c5158acbe4364e2543348cc834fc5feb9f723688303466f3ee1' 
  AND token = 'y2ITwpEOhuMUmCQscKbgVMNO364h3RpZMRIMIyxRr3c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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