SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '467c9c7e65a327c002f5cc36357d8fb1a1db4afcd220e29afbb9768021d8e349' 
  AND token = 'IiEjdzbHse3+zUiUSe4FGZmk7sDhP115UChA7X0wlt8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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