SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd9a746c8caa0978b74a7275b701a0dabad99eefb29f2e7e5a8bb8db1da1eaa9c' 
  AND token = 'E6FFuOgJE6EfXgzGtRyCcQA1DZ0+h/HAc1+iTcKZvoQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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