SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b36beff3bdbfd76b47d28190e61d1ec79cb557dd9536045892038020c61d232d' 
  AND token = 'F0nYxCZLF+3JRlglPY9ZGBgVod6/EnrAAAwznP4HT/s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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