SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '779b42fb3b90105790836d3025378dc0c4a253de3428fcabd6318255d193bd7f' 
  AND token = 'DtYkFd9I+jhvdOWklrSaqxBeyM4Epz89y78XvVfPEew=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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