SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '77d86aef209058b61c69c726b69bd79ee6937ad170bf6a9d0e3079f8be050edf' 
  AND token = '2y5K8eRjcZXls23/e1I8tr3dXxk8/+qAG2WuokMLcRM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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