SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '48542320f7716b8634b1aba434a7291268634a9ffd49656b8da99f423e6a5dd9' 
  AND token = 'jYATVZZw4jD2m+tRZyEhMeZMiAPIH0k16lAmjLI2G6w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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