SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b487e0359d79caecb26a6fd3e23a7d3a814dacd9ba867a5d84171abfcf38c517' 
  AND token = 'IGRFasQ7tVggWyQzuYRxDeTiu4KNQiWvDRmQH2ZzorE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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