SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '515ee65268fafad5141d28e2d1eb3ce64ef951878084dff1b787c33589b1c54d' 
  AND token = 'wbRqun94sKDDqHmDXJ7mDgXD+Y7ci6RpNZzdUO0GMcw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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