SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '75e757dcd2338a83ca4a9c5f8879595465ee9026e58e4ec900d9b3fca44059db' 
  AND token = 'S7t+/zc0YK8mKAztX5/5et3GIEH0wMZ3sBceMmFoKEE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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