SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '60be3f24fb02cc7bf250200c80f230f9ca0e75809512f3453a3952acb60a8b16' 
  AND token = 'IzX9wKlLBA3C2E1kngOk6fLGLd8EQuj+5SwQgCXj5Q8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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