SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '48050ae01adbbec02056aff4e566dff22636c3775bc7dea873ce24973eefa37f' 
  AND token = '3drHOQOqMFG2Lzvwrp45/pA9aa5Rz3cZlxOiXZpSFC8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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