SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '25693ce6867a94123fb41545e9879d4fb006d513a38377af95dd2cb3869dab22' 
  AND token = 'v496MJ4OGy91nJOyeUjw34lBGogBhqLxpBQWe3DSlPQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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