SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '19914dd33440c0a2fbfe2ebc473f4178ba339866b69f3a08079ab78569b6f729' 
  AND token = 'htEux3aTGMt+2XaIgUGnCO6ovizpfQQIRavn+71fyss=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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