SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bfb52f583c358d0a48ddec47e3179f4efdf50ef52a00bcc072292714c3c6002d' 
  AND token = '16eEbeysHAZ/D0VLNO29JjoecBaFTamUgOsX8HXtbf0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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