SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3d54bb8e89a78d47bd6baeb50d19b1e9aea228ac25635db1f89e11f26951d6c1' 
  AND token = '+lmSlTux56VaULRWm3EgVqqEOOgf/vYzy8FKUBfbDUw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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