SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '76dafb00a8bc29c88876576bc575136f58268babf0ba00431766b4038e73cb5e' 
  AND token = 'GqhC0AoOrZJyLBq4xOZzkaRcAYzlNGZtWYbIq5aGTYw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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