SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd856b8d522fec5370557129edfd2e31e81b5982e5977878d904cf30374c4438a' 
  AND token = 'ZVAAzLWIYcReyTvo0Yq3lRIHKlUHMjmScFTV2wh8cEA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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