SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'd427c87245da3ec6b2abdcf061c36f904a29e23513fd1e82b700ee6e9572ec62' 
  AND token = 'qjcAFKs3t5s2omEqaTthBhpllqouWB6nCgSW0K/adQo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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