SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e56828b5d732ec64c95bc7ee42a85beeaa0f4e08322507d26b94fb8bac039f29' 
  AND token = '6eNVy9UtjMe1PO6Cdfyiv05NNdK/pM3LbHn8WQxH/n4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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