SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'fa78690e3280d5e7d45f23968827984dc94ed89f453d69537d216111694c2ed8' 
  AND token = 'dETmWdmBfuMw8Pq9u12ek1eUixSgJF/JI7y2+9uQQX8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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