SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fe3c59574aa882ab9b299df3bfb721f6c0fe44f074b34545227cd05fe11fc559' 
  AND token = '6JpiLx9/FruPh9Znkygbh4ljXDhz2E8ifdye1h9xkI4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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