SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6a2a90d0dea55082b7559effcd425be5d9d89f785b7aeade894b76278443358a' 
  AND token = 'vNkuuOqfhp841ubS/ICkMLqU47M97twj40p3KqVxHDE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}