SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd5cf6b587943c9877c80e6b261684532dfae7d81a035525c4a585580b0d620c5' 
  AND token = 'yVxDQcbBZtp+rfCmQsfvyy1SeztgboAQZzgjL9QP0Vc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}