SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '123b9cbb9225446a686f418482055839195b2e6417cb7ba62187173fb7623daa' 
  AND token = 'n1QndyMJgwN0F6hDOQNgadSafCJMDMT7Ug63YOLFGww=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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