SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '10c506a1509e12c103abbd392b00d733878bc8c9095125bf75eac5f4e5e414c4' 
  AND token = 'WYrlJ9jdEOqq72HjhjwptCWbpga8voTZP6fQKwkc3Po=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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