SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'fa21b5726c895fcb6b01289ba59596c8fa3213f6db0042e6d303d391dd840681' 
  AND token = 'MQezzgxVD5vfPiHmRKCuZp1AlFCyyK7A68gJRlq3cCc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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