SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '0f8d6227c06d5972c3976d7595ac0266bc79c45cef418712fecc5ed84ffab132' 
  AND token = 'ZusGkQYcgcK47PEFtSQiU+tQGg+Dgofty5pq3RVrJ0w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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