SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5120d2e254725600e88555db8906f3185184ca08f1cb0ff024609a0c937c83b5' 
  AND token = '8e0VgJfoP2TzPBSm/1nmcvDQmPJcrRd/6Yd+6FC/MUM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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