SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c3f514095dd5d3d10f08282f9c18ba2caafd16f693e09cfee041a6b13bed6e39' 
  AND token = 'LHdOVtvDKZE0CqvA9iHK43Fhy5nJngxSomXwv42cdg0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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