SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '74d6447ebc2dc8132e8dd36125b8653edb09f55345f6d17efbbcb39c64559237' 
  AND token = 'xMbrYDyL4vMkbyfnFjvb9setSLXdXyCg/BwpfsKESiY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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