SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '501246036e4c9fdc0520b651f80f8bf9b1a04296b8d57c93afb665dbf3445d37' 
  AND token = '9932tRnTf65EU2U0nkM51nFspneKcVMABZsm05gsNpk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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