SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'ad7b78485e86fdfe33adfa3978f1e85b82338beb8e02e29f0e6bcaef903a4cf7' 
  AND token = 'osOkI9J5eF0i+/Brfxm/Hdvblwm0hqfnzFK8mYOp2yQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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