SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3911416296b94cfbd7012cf49d2007796cd51f83007f2bcda4933fbc437f8dc4' 
  AND token = 'xg/PGWzmbEazkj36NaDhHls84AtGkWK/oIOG6+vcALs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}