SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '861e70ce6950638ef7d802eed5edf2260cfc5e082dc81d3c6d8215a1d0b32b64' 
  AND token = 'BhXVEZ+jtSs4vX+uiCSGfD/GmNqPTvTACZLVHTxYDgo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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