SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aca9312c4cf4a87be5f91d6fd6d3ed993b140d848682c4c16c8c4c5f2f32eb82' 
  AND token = 'QeVVzm+XqqGNNQ3XRmSwpu3eo45BibMUztJx/t/gBuA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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