SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f7f46494c2f34de2a0bfb82ad906edf9315c6b8e7a466856e91124388bf45433' 
  AND token = '6oQ6ZqwAJknCvTxpWhbsBczP+zZfJWj98/B2GW5j8jQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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