SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '79719f31f87858af23977268153a7a58aac1a9361096828667f2715e1b123d16' 
  AND token = 'wYQM6GN2GOYFNIQUQ+/Ajuqdu9ZfsRZltA+VlzBXv3w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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