SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '87996ad375d5b19a12fb17c2099a195ccde31bf2a8a6a2a10b72434762070df7' 
  AND token = 'PKVrZyicsMhKr80fXUC2xhnF8xq4GpHnZFFBdzQbwuY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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