SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7c1edbd73890e27c541cde69c63c64f94fcddfd146ad4ef3f406ab528bed09eb' 
  AND token = 'BigBnGE4sGTyz+zcWExdX/Szx3uow7kXkDoA15ymIS0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00009

JSON explain

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