SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd7786346321889c46646aa4df4d6ee5a37747adeeeb6b9c8f8c731afde01eae3' 
  AND token = 'xJUi+tWTbyOHbLbp+208uR6OYWWuIMbw1ViPmaLJFpA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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