SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '959acac3aa7f900e32fae118a0017a77c94ebab4c1bd7e69b0159c32d532bb59' 
  AND token = 'uWXdep4vIq7imLX17ecg6HoRN58iLjK9ypX+7QMcAu4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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