SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e48aa965e2e5352ec0bdfe7b16324ea54686ebc3ab1281655b23b0816b3231fc' 
  AND token = 'v5HDBzixnSTpQZDd6AQJIA3KKMafY8sUVqXcla1+fRY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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