SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '528c41fdd0965d0b454f3a0a475397ad1edad3a6741dcf1e8fb3c335778737eb' 
  AND token = 'ihs5pbGDIrzBq8nfChnyySq1lPxjetXeoBUMy9tizc4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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