SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '12fef5f25b1822dd549dd171bc78b3965d7ee633dc58dd7d4bf713543c4d55b4' 
  AND token = '/M2FGxvMnNrMBW/uoJYF7LkFz8Nouc58BTrDA/KtRgc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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