SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6cfd373208e9eed6d862aba1151716d787ed2e64a89d86cf745ea791442480b9' 
  AND token = 'alCSevBXkzHDXVSuza/GIKeIiHQ5KynsCe+n9k0casg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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