SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0427e93f8afbfd4d1c029dd4c7be7603603742e0be63c9859a33bfb83c7a5539' 
  AND token = 'zssWTITy9qu3BmVWxITiDCsFGCNx8Ooxm+pwS8lCrbI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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