SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd561fcb4b33c37e18355a68392a97ef7ec0c2682f89c349c78aeddc9695ffe38' 
  AND token = '6atpx4Lp+bXRwOkHz2cLmjRWgA3nDS4ANuKqwZTJFVs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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