SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '381cd0984349e87513eacc0835976ca441774f09dd712283c9a2998e59f6070b' 
  AND token = 'yzT8j9UWTHhoTpElaeSjqaxio41n7lvKKRcp0rNuDBw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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