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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a9a2fd6cf3f9ac014d553afb635662e96abf6a21f7ac38ca8b7c5e22673d848f' 
  AND token = 'TAK5Ry6BfIiH9h+rq0qWgLenFVc0vg23j5M9v9T9GFE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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