SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '27d685f52580803f532d82fd852f507fb5faa59ebe9b0652274ed4b5e7873982' 
  AND token = '7w0zc94Hu4IxIYfAAjrIUtZZRZGWciXvTItbPqd3bk4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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