SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '668948c6966815bc896308e014db92ee1824139547d95b98cc9c33e34e2aa9aa' 
  AND token = 'gAFSjLqFc2/RXrAOb+SdcBYBesbCfGTleMPt7fo88WE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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