SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'ec4f17ff6337502c5f0b793934a8de1a86ff265c39f0d1bed78f737c1b879b42' 
  AND token = 'LmZVtvC/VbmtKlLkx6e5u2UKSivzqynJQYqJPDjr9+s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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