SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e1b74df551e098189f8897b1daf03d6fe722942b86e3bb599ba642f284b5c5fa' 
  AND token = 'b7JhBdO3OUzHs/r0BvjLAO5wGUKCkhTFVCGrTXCkP6s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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