SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9b8272e75928026c02bc28bc8ad2a21fdc4279852e21554e64734270d415f6eb' 
  AND token = 'LuaeQ4Zy1idjL/R5BOoLFymeriPx1X8WCIM+CzMN14g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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