SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '108aff625f24e0de2c0577d7ef99e10e7a643a1875acd5f98381a609b92eed5b' 
  AND token = '7jwjqqhIPblj+U9Ea6ImBXogNsJtuOaGr0OVsfi0J6g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00055

JSON explain

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