SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6183db39a762da1fac546175a9e2900790b5ee40294c0e9a5609e0d761896213' 
  AND token = 'k4BOZjXxGueIEUEzp+WBwfa8cAaR5ZMV1odg/ZnICfY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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