SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dfdf44d1786efe919a119b5a65cbcdb9b330168bb49188021e8998ec17bfcdcf' 
  AND token = 'lxOihXMOIZLEEHArVyUGNF1YLoa7fEcDVz963N/Nl0o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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