SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f5186a7bb4b1d3c00d486781bdd843c0bb81042694015a23d69882ef1e770eb1' 
  AND token = 'R4iXDojL60yqNbS98FIEVhYvf72TvxfwyVfJGTCDlxc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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