SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4ecbee6535810918f4c2c38ab6b28f0f3b02d6bd3f9f704f52123d056f50847b' 
  AND token = 'g3Do2rpM4Zk/djGDeWVpIubhSXzwVuwAdEGxZHXOHwQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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