SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '321174e25c106d17548ded3b93e72791589ffcf315983b54f73ef8694dd3ae9b' 
  AND token = 'v3C4yjC+TbITodwXIFBCPVsAnnPFJG5oleese8ALZKQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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