SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '7e1e7a8f82d0cf91885ee9b530d5122f8539de7afbda30509183b8876a2c3c54' 
  AND token = 'JFJiKNnpJAWYVNX/bryLsjQtezuwnBmztCUX8LozFXs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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