SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'fdc5968493baea8acdc21760ee400f93e8f1c7eefa4804ee58efcafee901b84b' 
  AND token = '6aR9WyoPrkgN8Ao1fa4MW/HgBKzQIf+Oxcoc2tR7iKM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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