SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0bc6f389742c07ba320b8f38282e0a1aac866aafd9d734c21377538410196d33' 
  AND token = 'kYodXWESqfIa7nalX0iUAVoQWAkEpKuv5ZspIanX5vc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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