SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '90f3738d10688bf730cf910941687edea1aaf6d3d74a24020c959573535f06fd' 
  AND token = 'YD/za6fleakr0oM4T5SL36tlKy2K9BVY7e+pxWFKrzQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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