SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '324b94002a8326a170ed5b9d113935735ab9e43dbfa0186cc7e6b83ceb2d6fd0' 
  AND token = 'SOu/sNZowOR7vRvAeOjamoZT8j5zuIwUC6Wgabd3pdE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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