SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bb90d3db40a9f7273a53e71f889e705ec0e620fae18eebede332981c67df5758' 
  AND token = 'zVzMDRdlZlG3kiXjGzpq59HG2LVRdeaU9fGsrQc87Vc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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