SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a401136e33c5ab81cabea633c8cf5f54b48d65b41867eec7d48f9935a7b7b2db' 
  AND token = 'kPTVGemypP1E7ylZChJN2L7vOGToJXl4PhzJgu/Xf04=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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