SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '30299a091d6efcdb37c6a846474941015a752f8b57b7f5272895e34490c8b2d5' 
  AND token = 'hvZ5RXc0xk+zO7ugab0gjRLvYkYGlHld4+Y9sWhgJzs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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