SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cb42850b037e05e39a43a73194bec32fb45f869bc76df2d18ef5ee87de83660c' 
  AND token = 'aUhyRdbd+AC37DywyuBp2Rw840QJru1sY5ksIIe3KSU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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